This study will determine the highest dose of idebonone that can safely be given to patients with Friedrich's ataxia, an inherited degenerative disease that causes loss of muscle coordination, speech problems, weakness and sensory loss. Enlargement of the left ventricle (the large pumping chamber of the heart) is also common in this disease. In studies in France and Canada, patients with Friedrich's ataxia who were given idebonone, an antioxidant similar to the dietary supplement coenzyme Q, had a decrease in the size of their left ventricle.